/*   
 * Copyright 2010 Rob Schoening
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *    http://www.apache.org/licenses/LICENSE-2.0
 *    
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.beaconframework.util.expression;

import java.util.Map;

import org.apache.commons.jexl.Expression;
import org.apache.commons.jexl.ExpressionFactory;
import org.apache.commons.jexl.JexlContext;
import org.apache.commons.jexl.JexlHelper;

public class JexlExpressionEngineFactory extends ExpressionEngineFactory {

    @Override
    public ExpressionEngine getExpressionEngine() {
        ExpressionEngine engine = new ExpressionEngine() {

            @Override
            public Object evaluate(String expressionString,
                    Map<String, Object> vars) {
                try {
                    Expression expression = ExpressionFactory
                            .createExpression(expressionString);

                    JexlContext ctx = JexlHelper.createContext();
                    ctx.setVars(vars);

                    return expression.evaluate(ctx);
                } catch (RuntimeException e) {
                    throw e;
                } catch (Exception e) {
                    throw new ExpressionEvaluationException(e);
                }
            }
        };
        return engine;
    }

}
